At a glanceThe Greyhound is the fastest dog on the planet, and is well-known for their racing background and streamlined physique. However, what is often overlooked is their sweet nature and their ability to be loving household pets. Today, many groups work to educate and promote the adoption of retired racing dogs, and also work to stop the sport (and business) of track racing. The greyhound’s origins date back to thousands of years ago, when they were often bred to help with game hunting.